Method for controlling air conditioner

ABSTRACT

In drying the interior of an indoor unit, room humidity (Rh) is detected by a humidity sensor, and a drying operation cycle, in which after first heating operation, which is weak heating operation in which a compressor included in a refrigerating cycle is operated at a low rotational speed, has been performed for a predetermined period of time, second heating operation, which is heating operation close to air blowing operation in which the compressor is stopped, is performed for a predetermined period of time, is repeated a predetermined number of times according to the room humidity (Rh). Thus, the indoor unit&#39;s interior can be dried properly without occurrence of dew condensation therein.

TECHNICAL FIELD

[0001] The present invention relates to a method for controlling an airconditioner. More particularly, it relates to a method for controllingan air conditioner which has an interior drying operation mode fordrying the interior of an indoor unit to prevent the development ofvarious bacteria and the emission of unpleasant smell in the indoorunit.

BACKGROUND ART

[0002] An air conditioner using a heat pump system has a heatingoperation mode and a cooling operation mode as the basic operationmodes, and at the time of the cooling operation mode and a dehumidifyingoperation mode (dry operation mode), condensed water adheres to anindoor heat exchanger included in a refrigerating cycle.

[0003] Usually, the condensed water is discharged to the outside of aroom through a drain pan, but it is not always discharged completely,and sometimes remains in the drain pan after the stoppage of operation.

[0004] In this case, dust etc. adhere to the remaining condensed water,by which fungus and other various bacteria develop and propagate, andthereby emitting unpleasant smell. Also, the humidity in the indoor unitis raised by the remaining condensed water, which also emitsextraordinarily unpleasant smell.

[0005] In such a situation, there has been proposed an air conditionerwhich performs interior drying operation for drying the interior ofindoor unit to prevent the development of various bacteria and theemission of unpleasant smell caused by the remaining condensed water(for example, see Japanese Patent Application Publications No. 9-126528and No. 10-62000).

[0006] The invention described in the Application Publication No.9-126528 is configured so that when the operation of air conditioner isstopped, air blowing operation or heating operation is performed for acertain period of time (for example, three minutes) to dry the interiorof indoor unit, and especially after cooling operation or dehumidifyingoperation, the interior of indoor unit is dried by prolonging thatperiod of time.

[0007] Also, the invention described in the Application Publication No.10-62000 is configured so that heating operation of air conditioner isstarted when it is detected that cooling operation has been finished,and during the heating operation, a compressor and an indoor fan arerotated at a low speed, and the operation thereof is performed for afixed period of time (for example, three minutes).

[0008] However, in the aforementioned invention described in theApplication Publication No. 9-126528, since the interior of indoor unitis dried mainly by air blowing operation using the indoor fan only, itinevitably takes time to sufficiently dry the interior of indoor unit.For example in a situation of high humidity, it is difficult tosufficiently dry the interior of indoor unit by drying operation for aperiod of time as short as three minutes.

[0009] Also, since the internal situation of indoor unit differsdepending on the operation time of cooling operation or dehumidifyingoperation, even if heating operation is additionally performed, when theheating operation time is fixed, the operation time for drying theinterior of indoor unit becomes longer than necessary, or contrarily theoperation for drying the interior of indoor unit becomes insufficient,which poses a problem in that proper drying operation is not performed.

[0010] In particular, the drying operation performed longer thannecessary is unfavorable from the viewpoint of energy saving, andcontrarily the insufficient drying operation leads to the development ofvarious bacteria and the emission of unpleasant smell.

[0011] In the aforementioned invention described in the ApplicationPublication No. 10-62000, since heating operation is started immediatelyafter cooling operation, humidified air with a relative humidity ofapproximately 100% is blown from the indoor unit, which sometimes givesunwell feeling to the user. Also, the humidified air may produce dewcondensation in the indoor unit. Moreover, since the heating operationtime is fixed, there arises the same problem as that with the inventiondescribed in the Application Publication No. 9-126528.

SUMMARY OF THE INVENTION

[0012] The present invention has been made to solve the above problems,and accordingly an object thereof is to provide a method for controllingan air conditioner, in which drying operation for the interior of indoorunit is performed properly according to the humidity in a room.

[0013] To achieve the above object, the present invention provides amethod for controlling an air conditioner comprising an indoor unithaving an indoor fan and a heat exchanger that is involved in arefrigerating cycle, the indoor fan and the heat exchanger arranged inan air passage connecting an air inlet port and an air outlet port, themethod comprising heat-exchanging air sucked through the air inlet portand blowing it through the air outlet port to control a roomtemperature, wherein the method has an interior drying operation modefor drying the interior of the indoor unit, and the method comprises: atthe time of the interior drying operation mode, detecting room humidity(Rh) by a humidity sensor provided in the indoor unit; and repeating adrying operation cycle a predetermined number of times according to theroom humidity (Rh), the drying operation cycle including: performing fora predetermined period of time, first heating operation which is weakheating operation with a compressor involved in the refrigerating cyclebeing operated at a low rotational speed; and then performing for apredetermined period of time, second heating operation which is heatingoperation close to air blowing operation in which the compressor isstopped, whereby the interior of the indoor unit is dried.

[0014] The present invention also embraces a mode in which by changingthe sequential order of the drying operation cycle, the first heatingoperation is performed for a predetermined period of time after thesecond heating operation has been performed for a predetermined periodof time.

[0015] In the present invention, the user can appropriately select theinterior drying operation mode by operating a remote controller. At thistime, specifically, when the interior drying operation mode isdesignated by a remote controller, a drying operation cycle is repeateda predetermined number of times according to the room humidity (Rh), thedrying operation cycle including: performing the second heatingoperation for a predetermined period of time; and then, continuing thesecond heating operation for a predetermined period of time if theoperation state before the start of interior drying operation is heatingoperation or air blowing operation, or performing the first heatingoperation for a predetermined period of time and subsequently performingthe second heating operation for a predetermined period of time if theoperation state before the start of interior drying operation isoperation other than heating operation and air blowing operation,whereby the interior of the indoor unit is dried.

[0016] The present invention embraces a mode in which at least when thesecond heating operation is performed, a vertical wind deflectorprovided in the air outlet port is directed in the horizontal direction.According to this mode, even if the blown-out air is approximately 100%humidified, because the second heating operation is heating operationclose to air blowing operation, dew condensation in the indoor unit isprevented effectively, and hence the degradation of room environment isrestrained.

[0017] Also, in the present invention, it is preferable that the numberof repetitions of the drying operation cycle be set at a higher value asthe room humidity (Rh) increases; when the second heating operation isperformed, the number of transmissions of a heating 0 code to thecompressor be counted; and the drying operation cycle be repeated untilthe count value reaches a predetermined preset value. According to thisconfiguration, when the room humidity (Rh) is high, interior dryingoperation is prolonged, and contrarily when the room humidity (Rh) islow, interior drying operation is shortened. Therefore, the interior ofindoor unit is dried efficiently and properly, so that energy saving isachieved.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 is a sectional view schematically showing the constructionof an indoor unit included in an air conditioner that is controlled by amethod in accordance with the present invention;

[0019]FIG. 2 is a schematic block diagram showing a control system forthe aforementioned air conditioner; and

[0020]FIGS. 3 and 4 are flowcharts for explaining the operation of thepresent invention.

DETAILED DESCRIPTION

[0021] A preferred embodiment of the present invention will now bedescribed with reference to FIGS. 1 to 4. The present invention is notlimited to this embodiment.

[0022] First, referring to FIGS. 1 and 2, this air conditioner has anindoor unit side control circuit 1 and an outdoor unit side controlcircuit 2, and carries out control necessary for room temperaturecontrol.

[0023] Upon receipt of a signal for drying operation for indoor unitinterior from a remote controller 3 operated by the user, dryingoperation for indoor unit interior is performed. At this time, properinterior drying operation is performed by switching over the content ofinterior drying operation according to the operation state before signalreception and the room humidity (Rh).

[0024] In this embodiment, an indoor unit is of a wall mounted type, andis formed with air inlet ports 4 a, 4 b and 4 c in the range from thefront surface to the top surface of a housing thereof. Also, an airoutlet port 5 is provided on the bottom surface of the housing, and avertical wind deflectors 5 a and transverse wind deflectors (not shown)are arranged to change the air blowing-out direction.

[0025] In an air passage connecting the air inlet ports 4 a, 4 b and 4 cand the air outlet port 5, an indoor heat exchanger 6 and an indoor fan7 are arranged.

[0026] In this embodiment, the indoor heat exchanger 6 includes threeexchangers 6 a, 6 b and 6 c, and these heat exchangers 6 a, 6 b and 6 care arranged in a Λ shape so as to cover the indoor fan 7.

[0027] The air inlet port 4 b arranged at a corner between the frontsurface and the top surface of indoor unit housing is normally open, andthe heat exchanger 6 b facing the air inlet port 4 b is provided with ahumidity sensor 8 for detecting the room humidity (Rh).

[0028] On the front side of the indoor unit housing, a receiving sectionfor receiving a remote control signal from the remote controller 3 isincluded, and a display section 9 for displaying the operation state isprovided. In the indoor unit, a drain pan 10 is provided to receivecondensed water dripping from the indoor heat exchanger 6 and dischargeit out of door.

[0029] As shown in FIG. 2, the remote controller 3 is provided with aspecial-purpose drying button 3 a for setting the interior dryingoperation. An outdoor unit is provided with a four-way valve 11, acompressor 12, and outdoor heat exchanger (not shown), which areincluded in a refrigerating cycle together with the aforementioned heatexchangers 6 a, 6 b and 6 c, and an outdoor fan 13 therefor.

[0030] The indoor unit side control circuit 1 not only controls the tiltof the vertical wind deflectors 5 a and the transverse wind deflectors(not shown) and the rotational speed of the indoor fan 7 according to anoperation signal from the remote controller 3, but also sends a controlsignal including an operation code of the compressor 12 according to thecurrent room temperature and the preset temperature to the outdoor unitside control circuit 2. Upon receipt of the control signal, the outdoorunit side control circuit 2 controls the four-way valve 11 and thecompressor 12.

[0031] To carry out the above-described control, the indoor unit sidecontrol circuit 1 includes a judgment section 1 a for reading theoperation signal from the remote controller 3 and judging its content, astate judgment section 1 c for judging the operation state of the airconditioner, a timer 1 b used at the time of execution of a routineshown in FIG. 3, a storage section 1 d, a counter 1 e, a rotationalspeed detecting section 1 f for detecting the rotational speed of theindoor fan 7, and a humidity judgment section 1 g for judging the roomhumidity (Rh) based on a detection signal from the humidity sensor 8.

[0032] The outdoor unit side control circuit 2 includes an operationmode judgment section 2 a for judging an operation mode included in acontrol signal from the indoor unit side control circuit 1 and acompressor control section 2 b to control the four-way valve 11, thecompressor 12, and the outdoor fan 13.

[0033] Next, one example of the control operation of air conditioner inaccordance with the present invention will be described with referenceto flowcharts shown in FIGS. 3 and 4.

[0034] First, as the basic operation, the indoor side and outdoor sidecontrol circuits 1 and 2 perform, for example, cooling operation orheating operation as general control necessary for room temperaturecontrol according to the operation signal from the remote controller 3.

[0035] If an interior drying operation signal is sent from the remotecontroller 3 when the above-described general operation is performed, orthe operation is stopped, the indoor unit side control circuit 1executes a routine shown in FIGS. 3 and 4.

[0036] When this routine starts, the indoor unit side control circuit 1first stores the operation state just before the start of interiordrying operation in the storage section 1 d.

[0037] Then, the four-way valve 11 is switched to the heating cycle sidevia the outdoor unit side control circuit 2, and a signal of operationcode 0 (rotational speed 0 rps) of the compressor 12 is sent and therotational speed of the indoor fan 7 is set at a low value, for example,900 rpm, by which heating operation close to air blowing operation isperformed. Also, the vertical wind deflectors 5 a are set in thehorizontal direction, and interior drying operation is displayed on thedisplay section 9 (Step ST1).

[0038] In the present invention, the heating operation state close toair blowing operation, in which the compressor 12 is stopped, is called“second heating operation”.

[0039] Succeedingly, a three-minute timer of the timer 1 b is started(Step ST2), masking is performed for one minute (Step ST3), and the roomhumidity (Rh) is detected by the detection signal from the humiditysensor 8 (Step ST4).

[0040] Next, it is judged from the content of the storage section 1 dwhether or not the operation state before the start of interior dryingoperation is heating operation or air blowing operation (Step ST5).

[0041] If the judgment result is YES and the operation state before thestart of interior drying operation is heating operation or air blowingoperation, the control proceeds from Step ST5 to Step ST6, where it isjudged whether or not the three-minute timer has expired. When the timerexpires, the interior drying operation is finished, and the operationstate is returned to the state before the start of interior dryingoperation, by which the routine is ended (Step ST7).

[0042] Thus, when the operation state before the start of interiordrying operation is heating operation or air blowing operation, thesecond heating operation is kept for three minutes to perform the dryingoperation for indoor unit interior.

[0043] Specifically, when the operation state before the start ofinterior drying operation is heating operation or air blowing operation,the indoor unit interior has already been dried to some extent, and ifthe second heating operation is performed, the indoor unit interior isdried sufficiently.

[0044] Also, at the time of the second heating operation, since theindoor fan blows weak wind, the room environment is not degraded.Although the operation time of the second heating operation is set atthree minutes in this example, the operation time may be determinedarbitrarily depending on whether the installation district of the airconditioner is a relatively cold district or a relatively warm district.

[0045] On the other hand, if the operation state before the start ofinterior drying operation is operation other than heating operation andair blowing operation, that is, cooling operation or dehumidifyingoperation (including operation stoppage), the control proceeds from StepST5 to Step ST8, where interior drying operation according to the roomhumidity (Rh) is executed by following the flowchart shown in FIG. 4.

[0046] In this case, it is judged whether or not the detected roomhumidity (Rh) is 80% or higher (Step ST10). If the room humidity (Rh) is80% or higher, the number of times of heating code 0 transmission is setat 4 in Step ST11. If the room humidity (Rh) is lower than 80% and notlower than 60%, the control proceeds from Step ST12 to Step ST13, wherethe number of times of heating code 0 transmission is set at 3. If theroom humidity (Rh) is lower than 60%, the control proceeds from StepST12 to Step ST14, where the number of times of heating code 0transmission is set at 2.

[0047] The rotational speed command of compressor is sent from theindoor unit side control circuit 1 to the outdoor unit side controlcircuit 2 with a transmission code. For the transmission code, therotational speed (rps) of compressor is represented by a numerical valuefrom 0 to 30, and a frequency code corresponding to the transmissioncode is prepared in the outdoor unit side control circuit 2. The outdoorunit side control circuit 2 converts the transmission code to thefrequency code, and thereby operates the compressor. The aforementionedheating 0 code is a transmission code in which the rotational speed ofcompressor is 0 rps in a state in which the refrigerating cycle is in aheating operation mode.

[0048] Succeedingly, it is judged whether or not the three-minute timerstarted in the aforementioned step ST2 has expired (Step ST15). If thetimer has expired, the control proceeds from Step ST15 to Step ST16,where a heating 0 code transmission counter included in the counter 1 eis incremented (+1 is added to the count value). In this case, becauseof first heating 0 code transmission, the heating 0 code transmissioncounter is 1.

[0049] Succeedingly, it is judged whether or not the value of heating 0code transmission counter is the value set in the aforementioned stepST11, ST13, or ST14 (Step ST17).

[0050] Specifically, when the room humidity (Rh) is 80% or higher, it isjudged whether or not the value of heating 0 code transmission counteris 4. When the room humidity (Rh) is not lower than 60% and lower than80%, it is judged whether or not the value of heating 0 codetransmission counter is 3. When the room humidity (Rh) is lower than60%, it is judged whether or not the value of heating 0 codetransmission counter is 2.

[0051] In the Step ST17, if the value of heating 0 code transmissioncounter is not the set value, a two-minute timer of the timer 1 b isstarted (Step ST18), and while the operation mode is kept in the heatingoperation mode, the operation code of the compressor 12 is set at 8(rotational speed of 39 rps), and the rotational speed of the indoor fan7 is set at 900 rpm (Step ST19).

[0052] Specifically, weak heating operation in which the compressor isoperated at a low rotational speed is performed. In the presentinvention, this heating operation state is called “first heatingoperation”.

[0053] Then, it is judged whether or not the two-minute timer hasexpired (Step ST20). If the two-minute timer has expired, that is, ifthe first heating operation has been performed for two minutes, thethree-minute timer is started (Step ST21), and thereafter, while theoperation mode is kept in the heating operation mode, the operation codeof the compressor 12 is set at 0 (stoppage), and the rotational speed ofthe indoor fan 7 is set at 900 rpm, by which the second heatingoperation is performed (Step ST22).

[0054] If the three-minute timer has expired, that is, if the secondheating operation close to air blowing operation has been performed forthree minutes while the compressor 12 has the 0 code, the controlreturns from Step ST23 to Step ST16, by which the above-describedprocessing is repeated.

[0055] Specifically, when the room humidity (Rh) is 80% or higher, afterthe first heating operation has been performed for two minutes, a dryingoperation cycle in which the second heating operation is performed forthree minutes is repeated three times. When the room humidity (Rh) isnot lower than 60% and lower than 80%, the drying operation cycle isrepeated two times. When the room humidity (Rh) is lower than 60%, thedrying operation cycle is executed once. The setting time of thetwo-minute timer and three-minute timer is one example.

[0056] After the drying operation cycle has been executed apredetermined number of times, the control proceeds from Step ST17 toStep ST7 in FIG. 3, by which the interior drying operation is finished.

[0057] Thus, as the room humidity (Rh) increases, the number ofrepetitions of the drying operation cycle in which the first heatingoperation (weak heating operation) and the second heating operation(heating operation close to air blowing operation) are combined isincreased. If the room humidity (Rh) is low, the number of repetitionsof the drying operation cycle is decreased. If the room humidity (Rh) isfurther low, the number of repetitions of the drying operation cycle isfurther decreased. Thereby, the indoor unit interior can be driedproperly according to the room humidity (Rh). For example, even ifcondensed water accumulates in the drain pan 10, the indoor unitinterior can be dried by evaporating the condensed water.

[0058] Also, if the special-purpose drying button 3 a on the remotecontroller 3 is operated, the interior drying operation in accordancewith the present invention can be performed, so that even if the airconditioner is in any operation state, the interior drying operation canbe performed appropriately as the user wishes.

[0059] Furthermore, in the case where the operation before the start ofinterior drying operation is cooling operation or dehumidifying (dry)operation, the room humidity (Rh) is relatively high, and moreover theindoor unit interior is made in a cooled state by that operation.

[0060] If the heating operation is started to dry the indoor unitinterior in this state as in the prior art (the invention described inthe Application Publication No. 10-62000), dew condensation is liable tooccur in the interior of indoor unit. However, the drying operation inthe present invention is drying operation in which the first heatingoperation and the second heating operation are combined, and thevertical wind deflectors 5 a are directed in the horizontal direction asshown in FIG. 1 to increase the amount of circulated air in the indoorunit. Therefore, dew condensation does not occur in the indoor unit, andthe indoor unit interior can be dried effectively.

[0061] Although the above-described embodiment is configured so that theinterior drying operation is performed when the special-purpose dryingbutton 3 a of the remote controller 3 is operated, the control methodcan be programmed so that the interior drying operation in accordancewith the present invention is performed automatically, for example,after cooling operation or dehumidifying (dry) operation has beenperformed.

[0062] Also, a control method in which in the drying operation cycleusing the first heating operation and the second heating operation, thefirst heating operation is performed after the second heating operationhas been performed is also embraced in the present invention.

1. A method for controlling an air conditioner comprising an indoor unithaving an indoor fan and a heat exchanger that is involved in arefrigerating cycle, said indoor fan and said heat exchanger arranged inan air passage connecting an air inlet port and an air outlet port, saidmethod comprising heat-exchanging air sucked through said air inlet portand blowing it through said air outlet port to control a roomtemperature, wherein said method has an interior drying operation modefor drying the interior of said indoor unit, and said method comprises:at the time of said interior drying operation mode, detecting roomhumidity (Rh) by a humidity sensor provided in said indoor unit; andrepeating a drying operation cycle a predetermined number of timesaccording to said room humidity (Rh), said drying operation cycleincluding: performing for a predetermined period of time, first heatingoperation which is weak heating operation with a compressor involved insaid refrigerating cycle being operated at a low rotational speed; andthen performing for a predetermined period of time, second heatingoperation which is heating operation close to air blowing operation inwhich said compressor is stopped, whereby the interior of said indoorunit is dried.
 2. The method for controlling an air conditioneraccording to claim 1, wherein by changing the sequential order of saiddrying operation cycle, said first heating operation is performed for apredetermined period of time after said second heating operation hasbeen performed for a predetermined period of time.
 3. The method forcontrolling an air conditioner according to claim 1 or 2, wherein whensaid interior drying operation mode is designated by a remotecontroller, a drying operation cycle is repeated a predetermined numberof times according to said room humidity (Rh), said drying operationcycle including: performing said second heating operation for apredetermined period of time; and then, continuing said second heatingoperation for a predetermined period of time if the operation statebefore the start of interior drying operation is heating operation orair blowing operation, or performing said first heating operation for apredetermined period of time and subsequently performing said secondheating operation for a predetermined period of time if the operationstate before the start of interior drying operation is operation otherthan heating operation and air blowing operation, whereby the interiorof said indoor unit is dried.
 4. The method for controlling an airconditioner according to any one of claims 1 to 3, wherein a verticalwind deflector for changing the blowing-out direction is provided insaid air outlet port, and at least when said second heating operation isperformed, said vertical wind deflector is directed in the horizontaldirection.
 5. The method for controlling an air conditioner according toany one of claims 1 to 4, wherein the number of repetitions of saiddrying operation cycle is set at a higher value as said room humidity(Rh) increases; when said second heating operation is performed, thenumber of transmissions of a heating 0 code to said compressor iscounted; and said drying operation cycle is repeated until the countvalue reaches a predetermined preset value.